Lupus in Newborns Predicts Heart Block in Siblings

Action Points

Explain to interested patients that a child born with neonatal lupus rash to a mother who has certain autoantibodies may predict possible severe heart complications in later children.

Identification of cutaneous neonatal lupus in a child born to an autoantibody-positive mother is essential, because it predicts a high risk of congenital heart block in subsequent offspring, researchers warned.

Among a cohort of mothers who had had a child with any manifestation of neonatal lupus, the rate of cardiac complications in a subsequent pregnancy was 18.2%, according to Peter M. Izmirly, MD, of New York University School of Medicine in New York City, and colleagues.

This represented a nearly 10-fold risk above the 2% rate reported in children born to autoantibody positive mothers who have not had an affected child, the researchers reported in the April issue of Arthritis & Rheumatism.

Neonatal lupus results from placental exposure to maternal anti-SSA/Ro or anti-SSB/La autoantibodies and most commonly manifests as annular or elliptical lesions on the head, trunk, and extremities.

The lesions themselves are benign, usually disappearing by six months, and often after having been diagnosed as seborrhea or dermatitis.

But the cutaneous lesions may be an important risk factor for serious involvement in subsequent offspring. Such children have developed conduction abnormalities, usually second- or third-degree heart block, as well as life-threatening cardiomyopathy.

Mortality has been estimated at 20% to 30%, and 67% of surviving children have required placement of a pacemaker before reaching adulthood.

Previous studies have found varying rates of neonatal lupus in affected families, so with the goal of more precisely determining the risks, Izmirly and colleagues enrolled 58 mothers from the Research Registry for Neonatal Lupus at the Hospital for Special Surgery in New York.

All mothers were autoantibody positive, had given birth to a child with cutaneous neonatal lupus, and then had at least one more child.

A total of 78% of mothers were Caucasian, and mean age was 32.

The overall recurrence rate of any manifestation of neonatal lupus in subsequent offspringwas 49.4% (95% CI 37% to 62%), the researchers found.

A total of 14 offspring had second- or third-degree congenital heart block, which was accompanied by cutaneous involvement in nine and hematologic/hepatic abnormalities in two.

Cutaneous neonatal lupus without heart block was seen in 29.9%, along with hematologic/hepatic complications in three.

One child had isolated hematologic/hepatic abnormalities, and there was one neonatal death.

About half of subsequent children were unaffected.

The research registry contains a number of asymptomatic women who were identified as having anti-SSA/SSB antibodies only after an affected child was born.

In addition, several cases of cutaneous lupus were diagnosed retrospectively, by examining photographs, after a subsequent child was found to have neonatal lupus.

In an effort to minimize potential referral bias in families with multiple affected children, the investigators also analyzed outcomes of the 39 children born prospectively after the initial child was enrolled in the registry.

In this prospective subgroup the overall recurrence rate was 35.9% (95% CI 20 to 52%).

Five children (12.8%) developed second- or third-degree heart block -- a six-fold elevation in risk -- which was accompanied by a rash in three and hematologic/hepatic abnormalities in one.

Nine children (23.1%) developed cutaneous lupus without heart block, which was accompanied by hematologic/hepatic abnormalities in three.

The remaining children were unaffected.

The investigators also looked for maternal or fetal risk factors that might be associated with congenital heart block, including maternal age, treatment with steroids, sex of the child, and breast-feeding, and found none.

Fetal genetic factors are likely to contribute, they said.

The high morbidity, mortality, and irreversibility of cardiac neonatal lupus highlight the need for preventive strategies, and particularly prevention of recurrences.

"This study now provides a robust rate by which to predict the expected frequency of cardiac [neonatal lupus] following the birth of a child with cutaneous [neonatal lupus]," they said.

The data also can serve as a reference point for family counseling and to emphasize the need for careful monitoring of these mothers during pregnancy.

Limitations of the study include the predominance of Caucasians and the possibility of bias because the neonatal lupus registry actively seeks affected families.

"However, if only the prospectively evaluated pregnancies are considered, the recurrence rate of [neonatal lupus] remains substantial," the investigators observed.

The Research Registry for Neonatal Lupus is supported by the National Institutes of Health.

One investigator was supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases, and two others were supported by the SLE Lupus Foundation.

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